1. Field of the Invention
This disclosure relates to a thin-film transistor (“TFT”) substrate and a method of fabricating the same.
2. Description of the Related Art
A liquid crystal display (“LCD”) includes two substrates, which face each other, and a liquid crystal layer, which is interposed between the two substrates. One of the two substrates is a TFT substrate. The TFT substrate includes a plurality of gate lines, a plurality of data lines, a plurality of TFTs, and a plurality of electrodes. A TFT is disposed as a switching device at each intersection of a gate line and a data line. In addition, pixel electrodes are disposed on each of a plurality of pixels, respectively, and are each electrically connected to a TFT, respectively. The gate lines and the data lines receive a signal from a driving circuit via their respective pads. Each of the TFTs transmits a data signal received through a corresponding data line to a corresponding pixel electrode in response to a scan signal, which is input to a corresponding gate line.
A commercially available method for disposing wiring on a TFT substrate is photolithography, in which a material is disposed and patterned by a mask process. However, photolithography involves a plurality of processes, such as a process of depositing a thin film, coating a photoresist material, mask alignment, exposure, developing, etching, and stripping. Thus, the processing time and the cost of products manufactured with available photolithographic processes are increased.
To reduce the cost of available photolithographic processes, a 4-mask process has been introduced. The 4-mask process omits one process from a commercially available 5-mask process in which photolithography is performed using five masks to form a TFT substrate. Since the 4-mask process involves fewer processes than the 5-mask process, manufacturing costs can be reduced. However, since the 4-mask process is still complicated to perform, there is a limit to cost reduction in available 4-mask processes. In this regard, it would be desirable to provide a method for fabricating a TFT substrate more simply in order to further reduce manufacturing time and cost.